This invention is broadly in the field of latch devices and is more specifically directed to latching means that is resistant to undesired opening movement caused by vibration of the members on which the latching means is mounted.
Latch means for enabling retention of closures, cabinet doors and the like are employed in a wide variety of devices and embody a similar large number of structural designs. All such latch devices should desirably provide a reliable, easy to use latching function. Unfortunately, many of the prior known devices, while satisfactory for use on rigid, firm support members, have not provided satisfactory performance when mounted on access doors or the like of equipment such as washing machines in which the latch members are subjected to substantial continuous vibration. More specifically, many prior known latching devices employing slide bolt means mounted for movement between a locking position and an unlocked position tend to move toward the unlocked position under the influence of the vibrational forces to which they are subjected. The foregoing is true even in the case of slide-bolt members in which spring means are provided for biassing the slide-bolt toward a locked position.
While it is possible to solve the foregoing problem by the provision of relatively complex structures such as over-center toggle linkages and the like, no simple, inexpensive and easy to use solution to the problem has been proposed prior to the subject invention.
Therefore, it is the primary object of this invention to provide a new and improved latch means.
A more specific object of the invention is the provision of new and improved latch means having latch locking capability resistant to vibrational forces imparted to the latch means by the members on which the latch means is mounted.
A still further object of the invention is the provision of new and improved latch means that is economical to fabricate, easy to use and reliable in operation.
Achievement of the foregoing objects is enabled by the preferred embodiments of the invention through the provision of a rotary latch lock mounted in association with a slide-bolt component of the latch device. The rotary latch lock is supported on a stub shaft for rotation with a compressible washer also being mounted on the stub shaft and biassed against one side of the rotary latch lock to provide a frictional resistance to rotation of the latch lock member. The engagement of the compressible washer with the rotary latch lock serves to maintain the rotary latch lock in any desired position of rotation but permits the latch lock to be manually rotated to such a desired position without undue effort. The rotary latch lock comprises a disc member having a cylindrical outer surface portion about a substantial portion of its periphery and having a chordal surface defining the remaining portion of its periphery. The chordal surface is spaced closer to the axis of the rotary member.
Positioning of the rotary latch lock so that the chordal surface faces means extending from the slide-bolt enables the slide-bolt to move toward the rotary latch lock to an unlocking position. However, the rotary latch lock can be rotated to a second position in which the cylindrical surface faces the slide-bolt when the slide-bolt is in its locked position. Engagement of the cylindrical surface with the slide-bolt when the slide-bolt is in the locked position serves to prevent movement of the slide-bolt toward the unlocked position. Moreover, the friction washer engageable with the rotary latch lock serves to maintain the latch lock in any position of rotation so that vibration will not result in movement of the latch lock to permit the slide bolt to become unlocked under the influence of such vibrations.
In another embodiment of the invention, the rotary latch lock is mounted on the slide-bolt in a position adjacent a fixed bracket lug for rotation about a stub shaft. In this embodiment, an identical compressible friction washer engages the rotary latch lock to maintain the latch lock in any given position of rotation while permitting manual adjustment of the latch lock without undue effort. The outer surface of the rotary latch lock of the last-mentioned embodiment is cylindrical for the most part, but is interrupted by a radial slot of a width greater than the width of the stop lug. Rotation of the latch lock to a position in which the radial slot is aligned with the stop lug enables movement of the latch lock and the slide-bolt to an unlocked position. However, movement of the slide-bolt to a locked position and positioning of the rotary latch lock with the cylindrical surface facing the stop lug prevents movement of the slide-bolt to the unlocked position. The members will remain in the foregoing position due to the operation of the compressible washer engaging the rotary latch lock.
A better understanding of the manner in which the preferred embodiments of the invention achieve the objects of the invention will be enabled when the following written description is considered in conjunction with the appended drawings.